Other Hardening Methods
Several different methods can be used to harden metals. Let’s discuss three major hardening approaches besides induction hardening, flame, furnace, and vacuum hardening.
The Furnace hardening process involves heating of workpiece into a heat treatment furnace in a controlled environment. The workpiece is heated until austenite transforms, after which a quick quenching occurs.
The furnace hardening cannot heat the workpiece as uniformly as induction hardening does. It heats all workpiece portions, while induction hardening can heat specific workpiece sections. Induction is a go-to option if you need to harden a particular portion.
Vacuum hardening involves heating the workpiece by controlling the partial pressure, followed by a quick cooling process. It is often used for high-precision parts, as it can produce tough and consistent surfaces with minimal distortion.
Like the furnace hardening, it is also incapable of heating the workpiece at a specific region. The vacuum prevents the workpiece from reacting with atmospheric gases in the air, so the result is unaffected.
Flame hardening also involves the hardening of the outer surface using a flame while maintaining the ductility of the core section. The depth capability of flame hardening ranges up to 10 mm. This process is typically used to harden small or thin parts or to harden specific areas of a more significant piece.
Since induction hardening does not use an open heating approach like flame hardening, it is more precise and does not create overheating, scaling, or decarburization damage.